Through three 90-minute debates and innumerable campaign appearances, the candidates have made precious little mention of the "fiscal cliff," a year-end whammy of tax hikes and budget cuts that could send the economy deep into recession. Nor has there been much discussion of such hot-button topics as climate change and same-sex marriage.

But perhaps nowhere has the silence been louder than on the issue of gun violence.

This is true despite the horrific January 2011 shooting in Arizona when a deranged college student opened fire at a shopping center, killing six people, including a 9-year-old girl and a federal judge, and gravely wounding Rep. Gabrielle Giffords.

And it is true even though 12,000 Americans a year, or 33 a day, die from gun violence.

The reason is no secret. The powerful gun lobby has made candidates wary of supporting even common-sense measures such as requiring background checks for gun-show sales, cracking down on rogue dealers, forcing states to do a better job of filing mental health records to a national database, and reinstating the ban on assault-style weapons that have no sporting or self-defense purposes.

The latter issue finally surfaced at this month's town hall-style debate in New York, when a voter asked the candidates about keeping AK-47s out of the hands of criminals. The answers were revealing.

Obama began with an ode to the Second Amendment and ended with a discussion of schools and communities. But in between, he at least allowed that the assault-weapons ban should be reintroduced in Congress.

The previous ban, which expired in 2004, also outlawed the sort of extended clip, containing 31 bullets, that was used in the Tucson killings. When the gunman finally stopped to reload, bystanders were able to tackle him. So it isn't so certain, as the NRA likes to insist, that gun laws wouldn't have made a difference.

The NRA mantra — tough prosecution of violent criminals — misses one little point. Prosecution of shooters is of cold comfort to the victims and their families. Putting the accused killers in the three recent massacres behind bars won't bring back 9-year-old Christina-Taylor Green or the 23 others gunned down in Aurora, Milwaukee and Tucson.